DESCRIPTION: The proposed project will explore the implications of evolutionary biology for the economics of family organization. Biologists have advanced the idea that successful genes will program the individuals who carry them to take actions that tend to maximize the number of their surviving offspring. In sexually reproducing species, successful genes will also program individuals to value the survival of full siblings at one-half the value that they place on their own survival. These ideas have powerful implications for economic relations between siblings and their parents, for sibling cooperation and rivalry, for patterns of marriage, and for the structure of household organization. The investigators will construct models in which the incentives of individual agents are those predicted by genetic models of natural selection, while the effects on the population as a whole are determined by the equilibrium interaction of such individuals under competition for resources and mates. They will use these models to explore and understand such institutions as extended family households, monogamy, polygyny, bride prices and dowries and they will investigate their testable implications.